Rocket having adjustable discharge passage



Oct. 7, 1952 sKlNNER 2,612,747

ROCKET HAVING ADJUSTABLE DISCHARGE PASSAGE Filed Jan. 25, 1945 Leslie Afikinner' a. amwxa M W perature decreases.

Patented Oct. 7, 1952 i I RocKET HAVING-ADJUSTABLE nIsc' A nGE,

SSAGE Leslie A. Skinner, Berkeley, Calif.', assigno'r town's United Statesof America as represented by the Secretary of War 'ApplicationJanuary 25, 1945, Serial No; 5514,59 1 I 3Claims. (o1. (so-ease) V Z:(Granted under the act of March 3, 1883,; as amended. April" 0, 1928 $70. ,G. 757).:

The inventiondescribedgherein may' bemanufactured'tand used by or for the Government'for governmental purposes without thepayment to me of any royalty-thereo'n.. v a

This invention relates to rockets. A purpose of the invention is to provide a means of varying the cross-sectional area of the passagewaythrough which the gases passout of the rocket casing.

A further purpose of the invention is toprovide a means for adjustingthe orifice cross-section of a, rocket. as the ambient temperature changes.

Another purpose of the invention is to provide a means for automatic adjustment of the orifice cross-section of a rocket for optimum performance depending upon ambient temperature, at

the time of firing.

Other purposes of the invention will become apparent from the following specification and claims' The accompanying drawing formin a part of this specification illustrates a preferred embodi ment of the invention. Inthe drawing,

Figure 1 is, a longitudinal sectional view of the rearward portion of a rocket including the invention, I

Figure 2 is a sectional view taken along the line 2--2ofFigurel, J 1 v t Figure 3 is a detail elevational view of a sta: tionary disk, v

Figure 4 is a detail elevational view of a movable diskand r Figure5 is a perspective detail view-of the disk shown in Figure-3. I

- It is well known that double base powders and others which are used for rocket propulsion having a burning rate which increases withan increase in ambient temperature at the tim the rocket is fired, and decreases as the ambient tem- Since a higher burning rate increases the rate of liberation of gases inside the rocket and hence the gas pressure, it is desirable to adjust the size of the gas discharge passageway leading out of the rocket to accord with the ambient temperature in order to. achieve op-v timum performance, by maintaining approximately constant pressure inside the rocket for a wide range of ambient temperatures. v

The adjustment may be made'by hand, or it may be automatic. This invention has as an important purpose the provision of means for making such adjustment before the rocket isfired.

In Figure l, gases are generated inside the rocket body casing l0 and follow the path indicated by the arrows l2 while passing out of the rocket into the air. The gases pass out through a nozzle M which includes a constricted portion l6 and an expanding portion l8. The inside diameter of the constricted portion 16 is constant from the point 11 to the point I 9 at which the latter point the inner casing surface diameter decreases radiallyrtoj point 20 which is alsorthe starting point o'f theexpanding portion of thenozzle. The contour a't point-29*is slightly rounded'as'shown; A disk 22-having: an outside diameter substantially equal tothe inside diameter of the casing l0 atipoint l9,'is inserted intothe' constricted portioni lsibf'jthe nozzle 14 with one face' 24 of the' disk. 22 hearing against the: shoulder 23 formed by the inner casing surface= between points. I9 and 20. Set 'sczewsZS-and 28 threaded through casing wall i D asshQWn, serve to hold The stationary disk 22; as is shown in' the detail viewsin Figures 3 and 5, has a'central longitudinal cut-out portion for passageway 30 extending througli the thickness of the disk, thepassagethe disk 22 tightly in place against the :shculder way 30' being formed with 'four lobes or grooves 32, 34, 36 and 38, the axes of the lobesbeing sep rated by ninety degrees as shown. 5

A second disk 40; shown in a detail v in Figure 4. is slightlysmaller in 'diarneter'than disk 22, and also has a longitudinal cut-outpertion or passageway 42 extending through the thickness of the disk-40, the passageway- 42 being the same size and shape as passageway 30 0f disk 22 and having four lobes or grooves 44,46, 48 and 5llasshown. V

Ball bearing 52 loos'ely insertedimre cessesfill are disposed about the periphery of movable disk 49 'as shown, and extend against the inner sun face of the constricted portion lfioffthe'nozzle {4 so as, to minimize friction "enc'ounteredduring;

1 movement or rotation of the movable disk 41).

The face 56 of the stationary disk 22 is provided with teeth 53 along its peripheral margin" as shown, and mating teeth'fifl are placed. on the peripheral'marginof the abutting face 62 of the movable-disk 40. The teeth extend-longitudinally outward from the toothe'cl'face of eachdisk' to permit the teeth of one disk to engage the teth of the other disk when they are brought together. The movable disk 40 is normally spacedsli'ghh ly. from the stationary disk 22, permitting the opposing. teeth 58 and fill'to clear each othe so that disk 4,0 may be rotated. Coiled springs 64 placed in recessesfififormed in stationary-disk 22 as shown, extend out of the face, 56 and press againstthe facegfiz of movableydisk 40 thus serving to keep lthe' nating teeth; 58 and 60 apart; Studs 67 and 68, are secured to the casing "10 by extending through :bores lB and 12, and have their threaded extensions fastened by nuts 14 and I6. The movable disk 40 is thus pressed against the studsbyfthe springs Mas-shown. Referring now to, Figure 2, it is seen that when disk 40 is rotated to the position. shown; the grooves 32, 34, ,38 and 38' of stationary disk 22 areforty-five degrees out of alignment with the grooves 44, 46, 48 and} of movable disk. 40so thatthe clear passagewayfor the gases-through elevation And when movable disk 40 is rotated forty-five degrees clockwise or counte r clockwise from the position shown in Figuref2, then each of the grooves of disk 40 is aligned with ..danger.is:tavoided,';in"the one case, of having the a groove of disk 22 and the;cleargas-passage- :pressure':rise.-sharply when the rocket is ignited way through the two disks i's'greatestzin crosssection. It is thus apparent that it is only necessary to rotate movable disk 149-, ,through forty-five degrees or one-eighth of a .complete, revolution to change the size o f the clear gas passageway from minimum tomaxiinumf j};

The rotation of movable disk "40 maybe made angular position until it is in the longitudinal axis of the nozzle the shorter leg will engage one of. the teeth Goof-rotatable disc 40. If-the longer-leg of the keyisnow rotated: about its aids the .disc 40. will be turned. The size of the gas passageway thus set for optimum performance depending on the ambient temperature ex isting at the time therocket is. ready; to be'fired. Or lthejdisks may be adjusted automatically by ardevic'e which changes the angular :position of the grooves of movablev disk 40' relative to the position of the grooves of stationary-disk .22 to suit the ambienttemperature. This may be done by means of a temperature responsive elent adapted to.rotategnovable'disk 40 as the elementaexpands or contracts due to temperature changes, so that no matter what the ambient temperature is, the gas passageway is of a size corresponding to. that temperature. Then, when the.rocket-is .to be fired, it is already set for proper gas passageway size-and needsnoiurther adjustment for this purpose. a

9 .-According .to .the presentinventiom. this is donenasshown in the drawingsby providing a stud .78 having ;.one end .8D.fixed into. a rec'e'ss 82. i n.- stationary disk 22 as shown .and-its .other end;'84,projecting into an arcuate recess 86 .formed in the matingQface .62; of .movable disk .40 as shown. A --temperature responsive element 98 ital-anti;as?1mama disk, i thereafter. By thus providing means for varying the outlet orifice v V V 4 crosssection to maintain the equilibrium condition of the gases inside the gas chamber at various ambient temperatures, the

to such ahig'hvalue as to explode the casing.

"Similarly i-ntheother case, the outlet orifice ficie'nt'valiietopropel the rocket.

While the-foregoing specification sets forth isplaced.- in the. recess 86 with one end secured v to-the stud 78 and the other-end secured to the end-90 of-the recess 86. Theelement vt8 may beof-any convenient design and as shown takes theform-ofa coiled'bi-metallic element adapted to -ex pandalong its'axis as ambient temperature-increases.

, :-As=;the.len'gthof the. element 88. changes, the disk"!!! is; thus. rotated relativeto; disk 122,. varying =the,g as, passageway cross-sectionfas. already explained. I The recess 86 isofdimensions sufficientlyglarge .to permit the ;.element 88 to per; for inits' lfun'ctionstherein.

, Assuming then a, given ambient temperature iust.- prior to firing the rocket, the present c'on-' and causing the teeth 60 on the movable disk v to'e'ngage and m'ate with the teeth'58 on'the sta tionary disk "22, thus preventing any further 'rothe invention in specific terms, it is to be understood that numerous changes in the shape, size, arrangementan'd materials mayibe .resorted to without'departinglfrom the spiritand-scope of the invention as claimed herein. lclaim: A 1.":In'Ia"rocket orfthe: like having a'ca'sing provided' with a :combustion chamber? an 'outwardly divergent nozzle axially aligned with said combustion chamber and a restricted throat :passage between-the said combustion chamber and the said-nozzle, rotatable means and'fixed'means in said throat passage, said rotatable means rand said fixed means having registering apertures cooperating to vary the size of the said throat, engaging means on corresponding facingportion of said rotatable means and said'fixed means, and yielding meanscooperating with said rotatable means and 'saidfixed means to urge'the said engaging means apart.-

2. In a'rocket or the like having a casing provided with a combustionchamber an outwardly divergent nozzle axially aligned with said cornbustion chamber and a restricted throat passage between said combustion chamber and said nozzle, meansin said throat passage forvarying the size thereof said means comprising a pair of discs in axial alignment, each of said discs provided with apertures adapted to register for maximum' passage area, one of said discs arranged for rotation relative to the other for reducing the said passage area, engaging means on corresponding facing portions of said discs whereby they may engage each other and a plurality of springs between thesaid discs urging them apart.

3. The combination as set forth in claim 2 in which the apertures comprise a central area having four-lobes'je'xtending radially therefrom, the axes of the said lobes being separated by ninety degrees,--and the engaging means comprise teeth arranged on the peripheral margin of the faces of. the :discs' LESLIE A..SKINNER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITEDI STATES PATENT Number Name Date 273,757 Morel Mar. 13, 1883 323,568 .Doherty Aug. 4, 1885 479,738 Cunningham July 26, 1892 961,179 Unge June 14, 1910 1,595,959 Barrows Aug. 10, 1926 1,901,852 Stolfayet al. Mar. 14, 1933 1,999,921 Burkhardt Apr. 30, 1935 2,063,592 Rochemont Dec. 8, 1936 2,072,556 Hibner, Jr. Mar. 2, 1937 2,481,059 Africano Sept. 6, 1949 FOREIGN PATENTS Number Country I Date 166,583 Great Britain July 11, 1921 

